80 Dr. Kane on the Compounds of Ammonia. 



1. ZWO. SO3. HAC?4"2HArf. 



2. cdo . SO3 . nxd -\- 2 hac?. 



3. NW . SO3, HAC?-|"2HArf. 



4. coo . SO3 . nkd -\- 2 nxd. 

 evidently corresponding to 



5. zreo.so3.HO-|-2HO, &c. 



The close relation which has been thus shown to exist between the most inti- 

 mately united portion of the amidide of hydrogen and of the constitutional water 

 of the magnesian class of sulphates, may be rendered still more remarkably 

 evident from the following examples. 



Anthon has discovered a peculiarly hydrated condition of the sulphate of 

 zinc, which has the formula zno . SO3 + 3|^ho. It crystallizes in rhomboids, of 

 which the exact form has not been determined ; this salt appears to be produced 

 under circumstances not yet completely known, but it would be most interesting 

 to ascertain exactly its crystalline admeasurement. I consider that the halving 

 of the equivalent of water in this salt results from precisely the same law as the 

 absorption of half an equivalent of ammonia by dry sulphate of copper, and that 

 its formula should be 



1. 27ZO. S03.HO + ZWO.S03-|-6hO, 



the ammonia zinc sulphate being 



2. Ho.sOg.HArf-f znoso3-f-6HO. 



In this salt, as I could not produce it at will, it was impossible to determine 

 whether the half atom of water was more powerfully retained, so as to give the 

 dry double salt 



3. zno . SO3 . HO -\- zno . SO3, 

 as there is 



4. cuo .sOj.uxd -{-cuoso^; 



but every thing would lead us to suppose it to be in a state of combination dif- 

 fering from the rest. 



In a family of the salts differing but very little from the ordinary alums, 

 there will be found some very remarkable examples of the similarity of action of 



